8238

Pilot Study of the Relationship Between Pitching Technique and Pain at the Elbow and Shoulder Joints of Youth Baseball Pitchers: A Prospective Cohort Study

Monday, October 19, 2009: 2:30 PM
Independence Ballroom F-H (Grand Hyatt)
Cynthia LaBella, MD, FAAP1, Tasos Karakostas, MPT, PhD2, Simon M. Hsiang, PhD, PE, CPE3 and Elisa Lawler, MS2, (1)Pediatrics, Northwestern University's Feinberg School of Medicine, Chicago, IL, (2)Motion Analysis Center, Children's Memorial Hospital, Chicago, IL, (3)Edward P. Fitts Department of Industrial and System Engineering, North Carolina State University, Raleigh, NC

Purpose:

Half of male baseball pitchers nine to 14 years of age report elbow or shoulder pain. While previous studies have demonstrated the incidence of elbow or shoulder pain increases with the number of pitches thrown, it is unclear whether specific biomechanical parameters of pitching technique are associated with elbow or shoulder pain in youth pitchers. The purpose of our study was to determine the relationship between pitching technique, as measured by three-dimensional motion analysis, and the incidence of elbow and shoulder pain in youth baseball pitchers.

Methods:

In 2006, we recruited 56 male baseball pitchers at Tanner stage 2 or 3 of pubertal maturation with no previous pain in the throwing arm from Chicago community baseball leagues. Subjects completed baseline surveys about their pitching habits and medical histories. From anthropometric and three-dimensional motion data, we calculated kinetic and kinematic parameters of the pitching motion for each subject. During the 2006 and 2007 baseball seasons, subjects reported weekly via a secure website the number of pitches thrown that week, and whether they had elbow or shoulder pain. We used t-tests to compare kinetic and kinematic parameters between subjects who did and did not develop pain.

Results:

Thirty-nine of the 56 subjects completed the two-year study. Six reported elbow and/or shoulder pain at least twice during the 2006 season (P). Twenty-four reported no pain during the 2006 or 2007 seasons (NP). There were no significant differences between P and NP groups for age (13.1 ± 1.3 vs. 12.5 ± 1.3), Tanner stage (67%T2, 33%T3 vs. 67%T2, 33%T3), BMI (19.8 ± 4.1 kg/m2 vs. 19.6 ± 3.1 kg/m2) or number of pitches per season (894 ± 404 vs. 849 ± 480). The P group had lower average shoulder elevation from the start of the pitching cycle to maximum shoulder elevation (38.9 ± 10.1 vs. 63.1 ± 20.7; p<0.05) and had greater shoulder internal rotation at the initiation of shoulder external rotation (13 ± 17.1 vs. -16.4 ± 28.8; p<0.05) than the NP group.

Conclusion:

This is the first prospective cohort study to demonstrate specific differences in pitching technique between youth baseball pitchers who do and do not develop shoulder or elbow pain. Our results suggest that teaching proper technique is important for preventing overuse injuries to the throwing arm in youth pitchers. A larger study is needed to confirm these results.